User Guide›Icing-potential alert

Icing-potential alert

A blue snowflake banner ❄ appears on the METAR only (TAFs carry no temperature) when the surface is cold and there's reported moisture — a partial, surface-level view of a much larger hazard.

The banner appears when both conditions are met:

Temperature is at or below +5°C, read from the report (e.g. 02/00 = +2°C, M03/M05 = −3°C), and
There is precipitation or water-based visible moisture — rain, snow, drizzle and similar (RA, SN, DZ, FZRA, -SHRA…) or fog / mist (FG, BR).

Example trigger: 2 1/2SM -SN BR … 02/00 — light snow and mist at +2°C. Dry obscurations such as haze (HZ), smoke (FU) and dust/sand do not trigger it, even when cold.

Important — this sees only part of the picture This alert captures only part of the icing spectrum — surface-level temperature combined with reported moisture. It is not inclusive of all conditions that can produce structural icing. Many icing scenarios it cannot see, including temperatures aloft, conditions within clouds, freezing levels, supercooled droplets, and forecast (TAF) conditions. The absence of this alert does not mean icing is absent. It remains the responsibility of the pilot in command to evaluate all available information and determine the presence and risk of icing conditions.